The D86 Distillation method is a measure of fuel volatility. The appropriate volatility range will assure maximum power output and fuel economy. This method is appropriate for diesel, diesel blends, gasoline, and gasoline blends.

The D93 Flash Point method reports the temperature at which ignitable vapors are produced and is a requirement for safe fuel storage and handling. This method can also be an indirect measure of fuel contamination, i.e. gasoline in diesel.

The D381 Washed and Unwashed Gum Content measures the amount of gum residues present in the fuel. Gums are varnish-like oxidation products that can cause sticking and plugging of moving fuel components. This test is most appropriate for gasoline, ethanol, gasoline blends, and aviation fuels. The D6217 and D7321 methods are better suited for diesel, biodiesel, and diesel blends.

The D381 Washed and Unwashed Gum Content measures the amount of gum residues present in the fuel. Gums are varnish-like oxidation products that can cause sticking and plugging of moving fuel components. This test is most appropriate for gasoline, ethanol, gasoline blends, and aviation fuels. The D6217 and D7321 methods are better suited for diesel, biodiesel, and diesel blends.

The D1688 Copper method determines the amount of copper in aqueous solutions. Copper is a very active catalyst for hydrocarbon oxidation and can contribute to gum formation in gasoline and gasoline blends. This method is typically used for denatured fuel ethanol and E85 blends.

The D4052 Density method measures the density of liquids. Standard density measurements are generally taken at 15.6°C and several measures of density can be obtained. Density is the mass per unit volume of fuel and is typically reported as g/mL. Relative Density and Specific Gravity are the same measurement and is the density of the fuel divided by the density of water at the same temperature. This value is unitless. API gravity is a calculated measure of density where low API indicates a high-density fuel and high API indicates a low-density fuel.

The D4052 Density method measures the density of liquids. Standard density measurements are generally taken at 15.6°C and several measures of density can be obtained. Density is the mass per unit volume of fuel and is typically reported as g/mL. Relative Density and Specific Gravity are the same measurement and is the density of the fuel divided by the density of water at the same temperature. This value is unitless. API gravity is a calculated measure of density where low API indicates a high-density fuel and high API indicates a low-density fuel.

The D4176 Visual Inspection provides a visual assessment of fuel quality. Procedure 1 looks for visual evidence of haze, water droplets, and/or sediment. Procedure 2 uses a numerical description for the strength of haze present in the fuel.

The D5191 Vapor Pressure method measures the vapor pressure exerted by liquid fuels and is given as the Dry Vapor Pressure Equivalent (DVPE) which very closely approximates the results obtained by ASTM D4953 Vapor Pressure (Dry Method). This test is most suitable for gasoline and gasoline blends up to 85 % ethanol.

At least 30 mL of sample required with between 20% and 30% headspace.

The D5453 Sulfur method measures the total sulfur content by UV fluorescence. This test is suitable for most liquid hydrocarbons and some solids (i.e. fats and feedstock materials) if they can be dissolved in toluene. This method is not suitable for glycerin.

The D5501 Ethanol Content method measures the ethanol and methanol content of denatured fuel ethanol and higher ethanol blends (E21 to E85). For ethanol contents below 20 % (E0 to E20), the D4815 method is more appropriate.

The D6423 pHe method measures the hydrogen ion activity (pH) of ethanol fuels. The pHe value is a good indication of the corrosion potential of the fuel. This method is not suitable for hydrocarbon oils such as diesel and biodiesel.

The D7319 Inorganic Chloride/Existent Sulfate method measures chlorides and sulfates in denatured fuel ethanol and E85 blends. Excess chlorides and sulfates can contribute to the formation of filter and injector plugging deposits.

The D7795 Acidity in Ethanol method gives a quantitative measure of acidic compounds in ethanol and ethanol blends and expresses the result as acetic acid. Even very low concentrations of organic acids such as acetic acid can be very corrosive to fuel components and so it is important to assure that these acids are in very low levels.

The D7872m Polymer Content by Gel Permeation Chromatography is a slightly modified method for determining the polymer content of liquid fuels. Polymers are commonly found in pipeline additives and cold-flow additives and, when in excess, can cause issues like filter plugging.

The E203 Volumetric KF Moisture method measures the level of moisture entrained in a fuel sample by Karl Fischer titration. This test is very sensitive and can detect water in the low ppm (parts per million) range. This method is suitable for any fuel sample but is more commonly used for samples with ethanol content, or for samples expected to contain higher concentrations of water.

Mass Spectrometry (GC/MS) can be used to identify unknown compounds or to give a more detailed look at the composition of a fuel product or feedstock material. This instrument has been especially useful for analyzing filter residue from plugged filters or analyzing fuel samples that may have been adulterated (vandalized).